In their paper, Mujal et al. (2017) describe as exceptional a section in the E Pyrenees (namely the Coll de Terrers), considering it a continental succession that continuously spans in time from the Late Permian to the Early Triassic. These authors describe the sandy-clayey red-beds of the upper Buntsandstein unit as the upper part of the Upper Red Unit (URU) and provide substantial stratigraphic and sedimentological data as well as palaeontological and mineralogical data in support of their thesis. We firstly have to consider that the post-Variscan deformation events altered the sedimentary contacts among the units (i.e. subsidence and tectonic evolution of the related sub-basins); and secondly, that the entire succession contains several tectonic structures affecting the late Palaeozoic-early Mesozoic sequence, due to the Alpine orogeny. The purported stratigraphic continuity between the Permian and Triassic is thus hampered not only by a different sedimentological and stratigraphical content but also by a complex tectonic framework.

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